I own many patents relating to various aspect of reciprocating slat conveyors. Such patents include U.S. Pat. No. 4,712,467, granted Dec. 15, 1987, and entitled, Combined Linear Hydraulic Motor And Transfer Valve; U.S. Pat. No. 4,793,469, granted Dec. 27, 1988 and entitled Reduced Size Drive/Frame Assembly For A Reciprocating Floor Conveyor; U.S. Pat. No. 4,821,868, granted Apr. 18, 1989 and entitled, Drive/Frame Assembly For A Reciprocating Floor; U.S. Pat. No. 5,103,866, granted Apr. 14, 1992, and entitled, Poppet Valve And Valve Assemblies Utilizing Same; U.S. Pat. No. 5,193,661, granted Mar. 16, 1993, and entitled, System Of Linear Hydraulic Motors; U.S. Pat. No. 5,361,679, granted Nov. 8, 1994, and entitled, Directional Control Valve With Pilot Operated Poppet Valve; and U.S. Pat. No. 5,622,095, granted Apr. 22, 1997, and entitled, Hydraulic Drive And Control System. The valve assembly of the present invention is particularly suited for use with reciprocating slat conveyors but it is believed to also have general utility.
The reciprocating slat conveyors disclosed by U.S. Pat. Nos. 4,712,467; 4,821,868 and 5,622,095 operate on what has been described the 1-2-3 cycle. This cycle is illustrated and described in my U.S. Pat. No. 4,793,469, with reference to FIGS. 2-6 in that patent. The conveyor is composed of slats that are divided into "sets" and "groups". In a typical conveyor, there are twenty-four slats divided into three "sets" and eight "groups." Each "group" consists of one slat from "set." Starting from one side of the conveyor, and moving inwardly, the first "group" of slats is composed of one slat from "set 1", then one slat from "set 2", and then one slat from "set 3." The next "group" ( "group 2") repeats this pattern and the pattern is repeated all the way across the conveyor, from "group 1" to "group 8."
FIG. 2 of U.S. Pat. No. 4,793,469, shows all of the conveyor slats in a retracted position in which common ends are aligned at a start station a. A load L is shown centrally positioned on the conveyor. FIG. 3 of that patent shows all of the conveyor slats being advanced together to move the load L forwardly. Movement continues until the opposite end of the conveyor slats are moved to a fully advanced position b. FIG. 4 shows the "set 1" slats being retracted while the "set 2" and "set 3" slats are held stationary. The load does not move because the frictional forces exerted on it by the stationary "set 2" and "set 3" slats are larger than the frictional forces exerted on it by the retracting "set 1" slats. FIG. 5 shows the next step in the sequence. The retracted "set 1" slats and the advanced "set 3" slats are held stationary while the "set 2" slats are being retracted. Again, the load L does not move. FIG. 6 shows retracted "set 1" and the "set 2" slats stationary and the "set 3" slats being retracted. Again, the load L does not move. In this example, the load L is moved a distance equal to the endwise movement of the slats, viz. a-c or d-b.
U.S. Pat. Nos. 4,712,467; 4,821,868, and 5,622,095 disclose a popular style of drive assembly for reciprocating slat conveyors. Each set of slats is connected to a separate transverse drive beam. Thus, in the example given above, there are three transverse drive beams. Each transverse drive beam is connected to a reversible linear hydraulic motor. The control system for the linear hydraulic motor includes a reversing valve, an on/off valve and a directional valve. The reversing valve is also quite commonly referred to as a switching valve. Example reversing valves are disclosed in the aforementioned U.S. Pat. Nos. 5,103,866; 5,193,661; 5,361,679 and 5,622,095. A typical on/off valve is designated OOV in U.S. Pat. No. 5,193,661. A typical direction control valve is designated DCV in U.S. Pat. No. 5,193,661.
A problem in existing systems is that the switching valve, the on/off valve and the direction control valve are separate valves that are spaced apart and connected together by conduits. This results in the system having a large number of conduits. The number of conduits dictates the overall space requirements for the system. The use of separate valves connected by conduits also can result in a positioning of the valves to where one or more of them are not be readily accessible.
There is a need for an approved assembly of the three valves in which the amount of tubing is minimized and the three valves are grouped close together and are rendered accessible to a user. It is a principal object of the invention to fill this need and provide such a valve assembly.